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stress vector variable calculation

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Old   December 11, 2020, 06:59
Default stress vector variable calculation
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SYL
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Hello!

I want to calculate the shear stress for my 3D flow in a channel in the streamwise direction. To do so I used the code below. I can obtain the shear stress for any given volume by integrating the calculated stress tensor.

However, I want to see the distribution of shear stress like any given variable i.e. the stress at each node. A couple of questions:

1) I've calculated tau for each node but i cannot find the variable for the normal vector. Would simply calculating, for example, {taux} x {Y Grid K Unit Normal} be appropriate for txy (t = stress vector)?

2) my fluid quantities are calculated in the cartesian x-direction but in curved channel areas I need them to be streamwise. I can adjust direction using the equation below, but i'm unsure how best to apply it to every node in a region.
Currently, my method is A) select region using pick & select tool, B) value blank to just show region, C) calculate variable using the above equation. It feels a bit clunky and i'm unsure of the results (at least until 1 is sorted). Is there a better method?

Equation for variable adjustment (t= stress vector):
t =ρ(tzx cosθ + txy sin⁡θ)

Code for calculating stress tensor:
{D} = {dUdX} + {dVdY} + {dWdZ}
{T11} = 0.00089 * (2 * {dUdX} - 2/3 * {D}) - {Pressure}
{T12} = 0.00089 * ({dVdX} + {dUdY})
{T13} = 0.00089 * ({dWdX} + {dUdZ})
{T22} = 0.00089 * (2 * {dVdY} - 2/3 * {D})-{Pressure}
{T23} = 0.00089 * ({dVdZ} + {dWdY})
{T33} = 0.00089 * (2 * {dWdZ} - 2/3 * {D}) - {Pressure}
{taux} = {T11} * {X Grid K Unit Normal} + {T12} *{Y Grid K Unit Normal} + {T13} * {Z Grid K Unit Normal}
{tauy} = {T12} * {X Grid K Unit Normal} + {T22} *{Y Grid K Unit Normal} + {T23} * {Z Grid K Unit Normal}
{tauz} = {T13} * {X Grid K Unit Normal} + {T23} *{Y Grid K Unit Normal} + {T33} * {Z Grid K Unit Normal}

Apologies if this has been asked previously - looked through the older posts and couldn't find anything.
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shear stress, tecplot, unit normal

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